1. Field of the Invention
The invention relates, in general, to movable barrier operators and, in particular, to garage door operators having systems for receiving data transmissions that are encoded or encrypted to identify one or more authorized users, optionally without regard to the particular transmitter employed.
2. Description of the Related Art
The garage door of many homes is controlled by a garage door opening system which protects against unwanted uses by means of electronically transmitted and received access codes. The access code systems now available provide a sufficient level of security so that for many homeowners the garage door is one of the primary means of entering and exiting the house. Home convenience and protection equipment such as garage door operators, lighting systems and security systems are coming to be viewed as necessities and not merely luxuries. These systems are often controlled by transmitters providing a radio frequency signal carrying coded information. For security, the coded information must be kept secret and can, for example, be taken from a large number of possible codes. For convenience, the transmitters and receivers they control should be simple to program.
Various controller systems have been proposed and/or manufactured using digital radio control and digital system processing, and allowing codes to be established by the user or randomly generated. In one system, a unique code is established at the transmitter using a number of two-position switches. The remote receiver also has a like number of switches to set the established code. For further information on the structure and operation of such a system, reference may be made to U.S. Pat. No. 29,525 to Willmott. In U.S. Pat. No. 4,178,549 to Ledenbach et al., the receiver recognizes a received signal from a particular transmitter by measuring and comparing relative durations of the pulse and non-pulse time intervals. Other systems have been proposed which do not require the user to set the code by operating switches on the transmitter and receiver. In one system, a random code generator at the receiver establishes the code. The new code is placed in the memory of a transmitter by holding the transmitter in proximity to the receiver which flashes the established code by means of a light emitting diode to a phototransistor in the transmitter. In another system, each transmitter has its own unique code. The receiver can store up to five unique codes. Should a transmitter be lost or stolen, the code for that transmitter can easily be removed from the memory of the receiver. For further information concerning the structure and operation of such systems, reference may be made to U.S. Pat. No. 4,529,980 to Liotine et al., and U.S. Pat. No. 4,750,118 to Heitschel et al., respectively.
Garage door operators have become more sophisticated over the years, providing users with increased convenience and security. However, further improvements are sought, such as ease of establishing the identity to the user and be granted access by either the receiver or transmitter component of a garage door operating system. Improvements for increasing the ease with which a user can generate data needed to set up a transmitter or receiver are continuously being sought. Further advantages have been sought in improving the ease with which a user can generate data identifying the user as one authorized to operate a transmitter, a receiver, or other components of a garage door operator control system. Further, it is desirable that the data developed by the user be suitable for encoding in a practical manner.